A. Solvent fractionation of palm oil to obtain fats useful as cocoa butter substitutes
British patent specification No. 827,172 to Best et al., published Feb. 3, 1960, discloses a process for obtaining a palm mid-fraction by removing from palm oil at least 50% by weight of a low melting glyceride fraction, and preferably 5-15% by weight of the highest melting glyceride fraction. Examples 2 and 3 provide embodiments of this process where palm oil is solvent fractionated in acetone by removing an olein fraction in the first stage and then a stearine fraction in the second stage. Examples 4 and 5 disclose embodiments of this process where palm oil is fractionated in acetone by removing an olein fraction in the first stage, a stearine fraction in the second stage, and an olein fraction in the third stage. U.S. Pat. No. 3,012,891 to Best et al., issued Dec. 12, 1961, discloses a similar process for obtaining a palm mid-fraction useful in cocoa butter substitutes. See also Example III(b) of U.S. Pat. No. 3,084,049 to Sinnema, issued Apr. 2, 1963, which discloses acetone fractionation of palm oil to obtain a palm fraction suitable in cocoa butter substitutes by removing an olein fraction in the first stage, a stearine fraction in the second stage, and an olein fraction in the third stage.
U.S. Pat. No. 2,903,363 to Farr, issued Sept. 8, 1959, discloses acetone fractionation of melted palm oil to obtain a fat suitable for chocolate coatings. In this process, the mixture of palm oil and acetone is held at 60.degree. F. to obtain a first set of crystals which are filtered off. The filtrate is then cooled to 30.degree. F. to obtain a second crop of fat crystals used in the chocolate coating.